Valve rotator

ABSTRACT

A valve rotator having a spring washer interposed between a spring retainer collar and a retainer cap, a plurality of radial ball-ramps being provided in the retainer cap with a ball positioned in each of the ramps in rolling contact with the spring washer, the balls being retained therein and biased radially inward by means of an annular spring engaging all of the balls.

United States Patent 1191 Slooten 1 51 Feb. 20, 1973 [54] VALVE ROTATOR[75] Inventor: Louis J. Van Slooten, West Olive,

Mich.

[73] Assignee: General Motors Corporation, De-

troit, Mich.

[22] Filed: Nov. 5, 1971 [21] Appl. No.: 195,982

52 u.s.c1. ..123/90.3,74/ss,137/331 51 1111.01. ..F0lll/32,F16k29/00 58Field of Search ..251/337; 123/9028, 90.29,

[5 6] References Cited UNITED STATES PATENTS Thorne ..l23/90.3

2,758,583 8/1956 Norton 2,827,886 3/1958 Geer ..123/90.3 2,841,1287/1958 Aiken 123/9029 2,863,428 12/1958 Norton v ..123/90.3 3,421,7341/1969 Updike et al ..251/337 Primary Examiner-Al Lawrence SmithAttorney-J. L. Carpenter et al.

[5 7 ABSTRACT A valve rotator having a spring washer interposed betweena spring retainer collar and a retainer cap, a plurality of radialball-ramps being provided in the retainer cap with a ball positioned ineach of the ramps in rolling contact with the spring washer, the ballsbeing retained therein and biased radially inward by means of an annularspring engaging all of the balls.

7 Claims, 4 Drawing Figures VALVE ROTATOR This invention relates to aspring loaded rotatable member and, in particular, to a valve rotator.

Specifically, this invention relates to a device for rotating a poppetvalve and, in particular, to a readily installed self-contained valverotator to impart rotary movement to a poppet valve each time the headof the valve is moved from its seat.

A number of different types of devices have been used in the prior artto effect valve rotation, one such type valve rotator includes aretainer cap carrying shiftable elements, such as balls, and a resilientmember which is deflected under increased load to transfer the springload from the retainer cap to the shiftable elements whereupon the loadon the shiftable elements causes them to rotate and produce rotationbetween the retainer cap and an adjacent nonrotatable member. In thistype of prior art device, each of the balls is positioned in an arcuategrooved ramp in the retainer cap with each of the balls being biased bya spring positioned in each groove in abutment against the ball withwhich it cooperates. In these devices, with the ball movable in a fixedpath as determined by the arcuate groove, the balls act on a limitedportion of the highly stressed resilient member so that rapid gallingthereof occurs. In addition, in such an assembly using, for example, sixballs as the shiftable elements, a minimum of fifteen parts are requiredto form each assembly of this type valve rotator.

It is therefore a principal object of this invention to provide animproved valve rotator having a reduced number of parts which is easy toassemble.

Another object of this invention is to provide an improved valve rotatorwhereby the load of the shiftable elements of the unit is distributedover a relatively large area of the resilient member of the valverotator.

These and other objects of the invention are attained by means of avalve rotator structure including a spring retainer collar and aretainer cap having a Bellevilletype spring washer interposedtherebetween. The retainer cap is provided with a plurality of radialballramps, each of which receives a shiftable element in the form of aball which is in rolling contact with the Belleville spring washer, theradial ball-ramps guiding the balls for radial movement in addition tothe normal tangential ball movement to allow the high unit loadassociated with the balls to be distributed over a relatively large areaon the surface of the Belleville spring washer. Each of the grooves isopen at its radially outward end to permit a single spring member to beused to normally bias all of the balls simultaneously, radially inward.

For a better understanding of the invention, as well as other objectsand further features thereof, reference is had to the followingdescription of the invention to be read in connection with theaccompanying drawings, wherein:

FIG. 1 is a sectional view of a valve rotator in accordance with theinvention mounted on a poppet valve of an internal combustion engine;

FIG. 2 is a sectional view taken along line 22 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2; and,

FIG. 4 is a sectional view similar to FIG. 1 showing an alternateembodiment of a valve rotator in accordance with the invention.

Referring now to the drawings, and in particular to FIG. 1, aconventional poppet valve 10 is mounted for reciprocation and rotationin a guide 12 of the cylinder head 14 of an internal combustion engine,not shown. The valve 10 is reciprocated by a coil return spring 16acting in response to valve opening movement induced by an engine drivenvalve rocker 18 acting against the top of the valve stem 20. As shown,the return spring 16 seats at its lower end against the cylinder headand at its upper end against the spring retainer collar 32 of the valverotator of the invention, generally designated 30, which is secured tothe valve stem by a flanged retainer 22 which is fixed as byconventional wedging keepers 24 to the valve stem.

The valve rotator 30, in the embodiment shown in FIGS. 1 and 2, includesthe spring retainer collar 32, acted on by the spring 16, a retainer cap34 held on the valve stem by the flanged retainer 22 and keepers 24, aplurality of balls 36 carried in inclined radial ball-ramp grooves inthe retainer cap 34 which are normally biased radially inward by acoiled garter spring 38, and a spring washer 40, in the form of aBelleville spring which is conical in shape when in a free state,positioned between the spring retainer collar 32 and the retainer cap34.

The spring retainer collar 32 includes a radially extending flangeportion 42 with a central opening 44 therethrough, an axial extendingflange portion 46 extending therefrom, which terminates in a radialinward extending lip 48, the latter being rolled over to the poshtionshown after assembly of the valve rotator to a posi-v tion to engage theouter rim of the retainer cap 34, as seen in FIG. 1 to limit axialmovement of the latter within the collar.

Retaining cap 34 is provided with an axial extending hub portion 50having a lower end surface 52 against which the inner edge of springwasher 40 is seated, the outer edge of the spring washer being seated onthe flange portion 42 of the retainer collar 32. Extending radiallyoutward from the hub portion is a flange 54, the underside of thisflange and the outer lower peripheral portion 51 of the hub portionbeing formed with radial ball-ramps 56, six such ramps being provided inthe embodiment disclosed.

As can be seen in FIG. 2, each ramp 56 is formed in such a manner as toguide a ball 36 therein to effect both tangential and radial movement ofthe ball. In addition, the upper surface or ramp surface 56a of eachramp, lower surface as seen in FIG. 3, is inclined at an angle to effectaxial movement of a ball relative to the valve stem.

Although the inward radial walls of the grooves are shown as beingstraight in FIG. 2, they could be curved in the form of a helix so thatthe grooves with their ramp surfaces 56a would in effect he in the formof a section of a conical-helix.

The relative width of each of the ramps 56 is such that a portion of aball 36 positioned therein will always extend radially outward from theouter lower peripheral portion 51 of the retainer cap. This is to permitthe balls to be normally biased radially inward toward the shallow endof the inclined surfaces 56a of the grooves by engagement with asuitable single annular spring member encircling the balls and the lowerperipheral portion 51.

In the embodiment shown in FIGS. 1 and 2, the annular spring member isin the form of a coiled garter spring 38. In the embodiment shown inFIG. 4, wherelike reference numerals indicate like parts, the annularspring member is in the form of a split annular metal spring ring 38a ofrectangular cross section. However, it is to be realized that theannular spring member can be of differing types, such as, for example, amultiple, tightly coiled spring of two or three coils, not shown, sincesuch a spring would be comparable in shape, but not in size or diameterof spring wire used therein, to the return spring 16.

The spring washer 40 should be of the desired stiffness so that when thevalve is in its closed position, as shown in FIG. 1, the main load ofreturn spring 16 is carried by the spring washer 40 with its outer edgeengaging the spring retainer collar 32 and its edge engaging the lowerend surface 52 of retainer cap 34. However, when the load force of thereturn spring 16 increases, as when the valve 10 is lifted from itsseat, the spring washer 40 should deflect and bow under this increasedspring load so that this load is transferred to the balls 36 in thegrooves of retainer cap 34.

Thus, in operation and with reference to FIGS. 1, 2 and 3, when thevalve 10 is in the closed position, the spring washer 40, still conicalin shape, carries the main load of return spring 16 with its inner edgein forced engagement against the lower end surface 52 of the retainercap. At this time, the spring member 38 biases the balls 36 radiallyinward toward the shallow end of the grooves with the balls engagedbetween the inclined surface 56a of the retainer cap and the uppersurface of the spring washer 40.

When the valve 10 is lifted from its seat, the load force of the returnspring 16 increases and, as this occurs, the spring washer 40 willdeflect and bow under this increased spring load to transfer this loadto the balls 36 in the grooves of retainer cap 34 with the inner edge ofthe spring washer then only lightly engaging the lower end surface 52 ofthe retainer cap. This transferred load on the balls causes them to rolldown the inclined surface 560 of the grooves against the biasing actionof spring 38 to thereby effect rotary movement of the retainer cap 34relative to the spring retainer collar, the latter being in effect fixedagainst rotation by engagement with return spring 16. This rotation ofthe retainer cap 34 relative to the spring retainer collar will effectrotation of the valve 10.

When the valve 10 is again moved from its open position toward itsclosed position, the load on return spring 16 decreases so that thisload is once again carried by the spring washer 40. Thus, as the springwasher 40 again returns to its conical configuration as shown in FIG. 1,its inner edge will once again engage the lower end surface 52 of theretainer cap 34 in the meantime releasing the load on the balls 36. Asthis load is taken off of the balls 36, the annular spring member 38 canthen again bias the balls radially inward and toward the shallow end ofthe grooves 56 so that these balls are once again snugly engaged betweenthe surface of the spring washer 40 and the inclined surface 56a of thegrooves. This latter movement of the balls 36 occurs without relativerotational movement between the spring retainer collar 32 and theretainer cap 34, since at this time, the inner edge of the spring washer40 is once again in loaded frictional contact with the lower end surface52 of the retainer cap.

From the above description, it is apparent that the radial movement ofthe balls in addition to the normal tangential movement of the ballsallow the high unit loading normally associated with these rotator ballsto be distributed over a relatively large area of the spring washersurface, thereby reducing spring washer wear caused by contact from therotator balls. Thus, the radial movement of the balls eliminates severeBelleville washer brinelling and surface metal fatigue, providing forincreased rotator life. In addition, for a given ball ramp incline and agiven length of ball travel, a valve rotator with radial ball-ramps inaccordance with the invention will have a slower rate of rotation for agiven engine speed than valve rotator with balls in arcuate ball-rampsto thereby effect a reduction in valve seat recession when nonleadedfuels are used.

What is claimed is:

l. A device for effecting relative rotation between two parts whensubjected to an increased axial load which comprises a first part and asecond part longitudinally aligned on a common axis for rotationrelative to each other and adapted to be axially loaded, a resilientmember positioned between said first part and said second part andarranged to transmit normal axial loads from said first part to saidsecond part, said second part being provided with a plurality of radial,inclined ball-ramp grooves, a ball element in each of said grooves inposition to engage one side of said resilient member and a singleannular spring means encircling said second part in position to engagesaid balls to normally bias them radially inward whereby said balls areadapted to rotatably drive said second part relative to said first partwhenever said resilient member is deflected under an increased axialload so the load is transferred to said balls by said resilient member.

2. A device for effecting relative rotation between two parts whensubjected to an increased axial load which comprises a first part and asecond part longitudinally aligned on a common rotational axis andadapted to be axially loaded, a conical shaped spring washer positionedbetween said first part and said second part and arranged under a normalaxial load so that its outer edge engages said first part and its inneredge engages said second part, said second part being provided with astepped annular radial extending flange with a plurality of radial,inclined ball-ramp grooves therein, a ball element in each of saidgrooves and positioned to engage one side of said spring washer betweensaid outer edge and said inner edge and an annular spring encirclingsaid flange in position to engage said balls to normally bias themradially inward whereby said balls are engaged between said springwasher and said ball-ramp grooves to rotatably drive said second partrelative to said first part whenever said resilient member is deflectedunder an increased axial load so that the load is transferred to saidballs.

3. A device according to claim 2 wherein said annular spring is anannular coiled garter spring.

4. A device according to claim 2 wherein said annular spring is anannular split ring of rectangular cross section.

5. A valve rotator for a poppet valve which is adapted to be mounted onthe valve stem thereof, said valve rotator consisting of a retainer capadapted to be fixed to the valve stem, a spring retainer collarencircling the valve stem and having a flanged portion to seat a valvespring, a spring member positioned between said spring retainer collarand said retainer cap and arranged to transmit normal axial loads fromsaid spring retainer collar to said retainer cap, said retainer caphaving a stepped annular flange with radial inclined ball-ramps therein,a ball positioned in each of said ramps for rolling contact with theresilient member, and an annular spring encircling said stepped

1. A device for effecting relative rotation between two parts whensubjected to an increased axial load which comprises a first part and asecond part longitudinally aligned on a common axis for rotationrelative to each other and adapted to be axially loaded, a resilientmember positioned between said first part and said second part andarranged to transmit normal axial loads from said first part to saidsecond part, said second part being provided with a plurality of radial,inclined ball-ramp grooves, a ball element in each of said grooves inposition to engage one side of said resilient member and a singleannular spring means encircling said second part in position to engagesaid balls to normally bias them radially inward whereby said balls areadapted to rotatably drive said second part relative to said first partwhenever said resilient member is deflected under an increased axialload so the load is transferred to said balls by said resilientmember.
 1. A device for effecting relative rotation between two partswhen subjected to an increased axial load which comprises a first partand a second part longitudinally aligned on a common axis for rotationrelative to each other and adapted to be axially loaded, a resilientmember positioned between said first part and said second part andarranged to transmit normal axial loads from said first part to saidsecond part, said second part being provided with a plurality of radial,inclined ball-ramp grooves, a ball element in each of said grooves inposition to engage one side of said resilient member and a singleannular spring means encircling said second part in position to engagesaid balls to normally bias them radially inward whereby said balls areadapted to rotatably drive said second part relative to said first partwhenever said resilient member is deflected under an increased axialload so the load is transferred to said balls by said resilient member.2. A device for effecting relative rotation between two parts whensubjected to an increased axial load which comprises a first part and asecond part longitudinally aligned on a common rotational axis andadapted to be axially loaded, a conical shaped spring washer positionedbetween said first part and said second part and arranged under a normalaxial load so that its outer edge engages said first part and its inneredge engages said second part, said second part being provided with astepped annular radial extending flange with a plurality of radial,inclined ball-ramp grooves therein, a ball element in each of saidgrooves and positioned to engage one side of said spring washer betweensaid outer edge and said inner edge and an annular spring encirclingsaid flange in position to engage said balls to normally bias themradially inward whereby said balls are engaged between said springwasher and said ball-ramp grooves to rotatably drive said second partrelative to said first part whenever said resilient member is deflectedunder an increased axial load so that the load is transferred to saidballs.
 3. A device according to claim 2 wherein said annular spring isan annular coiled garter spring.
 4. A device according to claim 2wherein said annular spring is an annular split ring of rectangularcross section.
 5. A valve rotator for a poppet valve which is adapted tobe mounted on the valve stem thereof, said valve rotator consisting of aretainer cap adapted to be fixed to the valve stem, a spring retainercollar encircling the valve stem and having a flanged portion to seat avalve spring, a spring member positioned between said spring retainercollar and said retainer cap and arranged to transmit normal axial loadsfrom said spring retainer collar to said retainer cap, said retainer caphaving a stepped annular flange with radial inclined ball-ramps therein,a ball positioned in each of said ramps for rolling contact with theresilient member, and an annular spring encircling said stepped annularflange of said retainer cap in position to engage said balls to normallybias them radially inward for snug engagement between said resilientmember and the surface of said ramps.
 6. A valve rotator according toclaim 5 wherein said spring member is a Belleville spring and whereinsaid annular spring is a coiled garter spring.